6.4

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DiffractionEventCalibrateDetectors v1

../_images/DiffractionEventCalibrateDetectors-v1_dlg.png

DiffractionEventCalibrateDetectors dialog.

Summary

This algorithm optimizes the position and angles of all of the detector panels. The target instruments for this feature are SNAP and TOPAZ.

Properties

Name Direction Type Default Description
InputWorkspace Input EventWorkspace Mandatory The workspace containing the geometry to be calibrated.
Params Input string   A comma separated list of first bin boundary, width, last bin boundary. Optionally this can be followed by a comma and more widths and last boundary pairs. Use bin boundaries close to peak you wish to maximize. Negative width values indicate logarithmic binning.
MaxIterations Input number 10 Stop after this number of iterations if a good fit is not found
LocationOfPeakToOptimize Input number 2.0308 Optimize this location of peak by moving detectors
DetCalFilename Input string Mandatory The output filename of the ISAW DetCal file. Allowed extensions: [‘.detcal’]
BankName Input string   Optional: To only calibrate one bank. Any bank whose name does not match the given string will have no events.

Description

Moves the detectors in an instrument to optimize the maximum intensity of each detector using gsl_multimin_fminimizer_nmsimplex. Only bin data close to peak you wish to maximize.

Usage

Example: move detectors to maximize intensity

import os
ws = CreateSampleWorkspace("Event",NumBanks=1,BankPixelWidth=1)
ws = MoveInstrumentComponent(Workspace='ws', ComponentName='bank1', X=0.5, RelativePosition=False)
wsD = ConvertUnits(InputWorkspace='ws',  Target='dSpacing')
maxD = Max(wsD)
#Peak is at 2.69 in dSpace
DiffractionEventCalibrateDetectors(InputWorkspace='ws', Params = "2.6, 0.001, 2.8",
    LocationOfPeakToOptimize=2.67, BankName="bank1", DetCalFilename="Test.DetCal")
LoadIsawDetCal(InputWorkspace='ws',Filename=os.path.join(config["defaultsave.directory"], 'Test.DetCal'))
ws = ConvertUnits(InputWorkspace='ws',  Target='dSpacing')
maxA = Max(ws)
print("Peak in dSpace {:.11f}".format(0.5*(maxD.readX(0)[0]+maxD.readX(0)[1])))
print("Peak from calibration {:.11f}".format(0.5*(maxA.readX(0)[0]+maxA.readX(0)[1])))

Output:

 Peak in dSpace 2.6...
 Peak from calibration 2.6...

Categories: AlgorithmIndex | Diffraction\Calibration | CorrectionFunctions\InstrumentCorrections